Thanks CD, that sets my mind at rest. Good of you to go to that effort for me. Have to admit that our garden pond at present needs a good clean out and the water is murky. We did have a pump and filter to keep it clean, but sometime during last winter a heron came calling, looking for a free meal, and hooked the pump out somehow, breaking the cable. The frogs and newts tell us they like the murk, and seeing as the heron ate all the fish we have left it for the time being.

The greatest part of wisdom is learning to develop  the ineffable genius of extracting the "neither here nor there" out of any situation...."